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We derive a simple empirical photometric redshift estimator using a training set of galaxies with multiband photometry and measured redshifts in the Hubble Deep Field (HDF). This estimator is model-independent; it does not use spectral…

Astrophysics · Physics 2007-05-23 Yun Wang , Neta Bahcall , Edwin L. Turner

We present a method, PhotoWeb, for estimating photometric redshifts of individual galaxies, and their equivalent distance, with megaparsec and even sub-megaparsec accuracy using the Cosmic Web as a constraint over photo-z estimates.…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Miguel A. Aragon-Calvo , Rien van de Weygaert , Bernard J. T. Jones , Bahram Mobasher

Precision cosmology requires accurate galaxy redshifts, but next generation optical surveys will observe unprecedented numbers of resolved galaxies, placing strain on the amount of spectroscopic follow-up required. We show how useful…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-07 Steven Cunnington , Ian Harrison , Alkistis Pourtsidou , David Bacon

We introduce ANNz, a freely available software package for photometric redshift estimation using Artificial Neural Networks. ANNz learns the relation between photometry and redshift from an appropriate training set of galaxies for which the…

Astrophysics · Physics 2009-08-21 Adrian A. Collister , Ofer Lahav

We present The-wiZZ, an open source and user-friendly software for estimating the redshift distributions of photometric galaxies with unknown redshifts by spatially cross-correlating them against a reference sample with known redshifts. The…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-10 Christopher B. Morrison , Hendrik Hildebrandt , Samuel J. Schmidt , Ivan K. Baldry , Maciej Bilicki , Ami Choi , Thomas Erben , Peter Schneider

We present a new approach to the problem of estimating the redshift of galaxies from photometric data. The approach uses a genetic algorithm combined with non-linear regression to model the 2SLAQ LRG data set with SDSS DR7 photometry. The…

Instrumentation and Methods for Astrophysics · Physics 2015-04-14 Robert Hogan , Malcolm Fairbairn , Navin Seeburn

We present a Bayesian reconstruction method which maps a galaxy distribution from redshift-space to real-space inferring the distances of the individual galaxies. The method is based on sampling density fields assuming a lognormal prior…

We perform an MMT/Hectospec redshift survey of the North Ecliptic Pole Wide (NEPW) field covering 5.4 square degrees, and use it to estimate the photometric redshifts for the sources without spectroscopic redshifts. By combining 2572 newly…

The determination of the galaxy luminosity function is an active and fundamental field in observational cosmology. In this paper we propose a cost effective way of measuring galaxy luminosity functions at faint magnitudes. Our technique…

Astrophysics · Physics 2009-10-28 M. U. SubbaRao , A. J. Connolly , A. S. Szalay , D. C. Koo

Four large-area Sunyaev-Zeldovich (SZ) experiments -- APEX-SZ, SPT, ACT, and Planck -- promise to detect clusters of galaxies through the distortion of Cosmic Microwave Background photons by hot (> 10^6 K) cluster gas (the SZ effect) over…

We investigate the impact of photometric signal-to-noise (S/N) on the precision of photometric redshifts in multi-band imaging surveys, using both simulations and real data. We simulate the optical 4-band (BVRz) Deep Lens Survey (DLS,…

Astrophysics · Physics 2009-11-13 V. E. Margoniner , D. M. Wittman

Imaging surveys of galaxies will have a high number density and angular resolution yet a poor redshift precision. Intensity maps of neutral hydrogen (HI) will have accurate redshift resolution yet will not resolve individual sources. Using…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-23 David Alonso , Pedro G. Ferreira , Matt J. Jarvis , Kavilan Moodley

The inclination of galaxies induces both reddening and extinction to their observed spectral energy distribution, which in turn impact the derived properties of the galaxies. Here we report a significant dependence of the error in…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Ching-Wa Yip , Alex S. Szalay , Samuel Carliles , Tamas Budavari

We extend existing methods for using cross-correlations to derive redshift distributions for photometric galaxies, without using photometric redshifts. The model presented in this paper simultaneously yields highly accurate and unbiased…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-07 Marcel P. van Daalen , Martin White

Accurate image reconstruction is at the heart of diagnostics in medical imaging. Supervised deep learning-based approaches have been investigated for solving inverse problems including image reconstruction. However, these trained models…

Computer Vision and Pattern Recognition · Computer Science 2023-12-04 Danyal F. Bhutto , Bo Zhu , Jeremiah Z. Liu , Neha Koonjoo , Hongwei B. Li , Bruce R. Rosen , Matthew S. Rosen

We present the first results of our application of photometric redshifts to the study of galaxy populations in high-redshift clusters. For this survey, we are examining a sample of galaxy clusters at z > 0.6 which have already been…

Astrophysics · Physics 2007-05-23 L. M. Lubin , R. J. Brunner

In order to answer the open questions of modern cosmology and galaxy evolution theory, robust algorithms for calculating photometric redshifts (photo-z) for very large samples of galaxies are needed. Correct estimation of the various…

Instrumentation and Methods for Astrophysics · Physics 2021-08-25 Oleksandra Razim , Stefano Cavuoti , Massimo Brescia , Giuseppe Riccio , Mara Salvato , Giuseppe Longo

Powerful current and future cosmological constraints using high precision measurements of the large-scale structure of galaxies and its weak gravitational lensing effects rely on accurate characterization of the redshift distributions of…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 Carles Sánchez , Gary M. Bernstein

Photometric redshifts are essential in studies of both galaxy evolution and cosmology, as they enable analyses of objects too numerous or faint for spectroscopy. The Rubin Observatory, Euclid, and Roman Space Telescope will soon provide a…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-28 Jeffrey A. Newman , Daniel Gruen

Traditional photometric redshift methods use only color information about the objects in question to estimate their redshifts. This paper introduces a new method utilizing colors, luminosity, surface brightness, and radial light profile to…

Astrophysics · Physics 2008-11-26 James J. Wray , James E. Gunn